#region Apache License
//
// Licensed to the Apache Software Foundation (ASF) under one or more 
// contributor license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright ownership. 
// The ASF licenses this file to you under the Apache License, Version 2.0
// (the "License"); you may not use this file except in compliance with 
// the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#endregion

using System;
using System.IO;

using log4net.Core;

namespace log4net.Util
{
    /// <summary>
    /// Subclass of <see cref="QuietTextWriter"/> that maintains a count of 
    /// the number of bytes written.
    /// </summary>
    /// <remarks>
    /// <para>
    /// This writer counts the number of bytes written.
    /// </para>
    /// </remarks>
    /// <author>Nicko Cadell</author>
    /// <author>Gert Driesen</author>
    public class CountingQuietTextWriter : QuietTextWriter
    {
        #region Public Instance Constructors

        /// <summary>
        /// Constructor
        /// </summary>
        /// <param name="writer">The <see cref="TextWriter" /> to actually write to.</param>
        /// <param name="errorHandler">The <see cref="IErrorHandler" /> to report errors to.</param>
        /// <remarks>
        /// <para>
        /// Creates a new instance of the <see cref="CountingQuietTextWriter" /> class 
        /// with the specified <see cref="TextWriter" /> and <see cref="IErrorHandler" />.
        /// </para>
        /// </remarks>
        public CountingQuietTextWriter(TextWriter writer, IErrorHandler errorHandler)
            : base(writer, errorHandler)
        {
            m_countBytes = 0;
        }

        #endregion Public Instance Constructors

        #region Override implementation of QuietTextWriter

        /// <summary>
        /// Writes a character to the underlying writer and counts the number of bytes written.
        /// </summary>
        /// <param name="value">the char to write</param>
        /// <remarks>
        /// <para>
        /// Overrides implementation of <see cref="QuietTextWriter"/>. Counts
        /// the number of bytes written.
        /// </para>
        /// </remarks>
        public override void Write(char value)
        {
            try {
                base.Write(value);

                // get the number of bytes needed to represent the 
                // char using the supplied encoding.
                m_countBytes += this.Encoding.GetByteCount(new char[] { value });
            }
            catch (Exception e) {
                this.ErrorHandler.Error("Failed to write [" + value + "].", e, ErrorCode.WriteFailure);
            }
        }

        /// <summary>
        /// Writes a buffer to the underlying writer and counts the number of bytes written.
        /// </summary>
        /// <param name="buffer">the buffer to write</param>
        /// <param name="index">the start index to write from</param>
        /// <param name="count">the number of characters to write</param>
        /// <remarks>
        /// <para>
        /// Overrides implementation of <see cref="QuietTextWriter"/>. Counts
        /// the number of bytes written.
        /// </para>
        /// </remarks>
        public override void Write(char[] buffer, int index, int count)
        {
            if (count > 0) {
                try {
                    base.Write(buffer, index, count);

                    // get the number of bytes needed to represent the 
                    // char array using the supplied encoding.
                    m_countBytes += this.Encoding.GetByteCount(buffer, index, count);
                }
                catch (Exception e) {
                    this.ErrorHandler.Error("Failed to write buffer.", e, ErrorCode.WriteFailure);
                }
            }
        }

        /// <summary>
        /// Writes a string to the output and counts the number of bytes written.
        /// </summary>
        /// <param name="str">The string data to write to the output.</param>
        /// <remarks>
        /// <para>
        /// Overrides implementation of <see cref="QuietTextWriter"/>. Counts
        /// the number of bytes written.
        /// </para>
        /// </remarks>
        override public void Write(string str)
        {
            if (str != null && str.Length > 0) {
                try {
                    base.Write(str);

                    // get the number of bytes needed to represent the 
                    // string using the supplied encoding.
                    m_countBytes += this.Encoding.GetByteCount(str);
                }
                catch (Exception e) {
                    this.ErrorHandler.Error("Failed to write [" + str + "].", e, ErrorCode.WriteFailure);
                }
            }
        }

        #endregion Override implementation of QuietTextWriter

        #region Public Instance Properties

        /// <summary>
        /// Gets or sets the total number of bytes written.
        /// </summary>
        /// <value>
        /// The total number of bytes written.
        /// </value>
        /// <remarks>
        /// <para>
        /// Gets or sets the total number of bytes written.
        /// </para>
        /// </remarks>
        public long Count
        {
            get { return m_countBytes; }
            set { m_countBytes = value; }
        }

        #endregion Public Instance Properties

        #region Private Instance Fields

        /// <summary>
        /// Total number of bytes written.
        /// </summary>
        private long m_countBytes;

        #endregion Private Instance Fields
    }
}
